This invention relates generally to spray gun assemblies and more particularly to such spray gun assemblies which are adapted for heavy industrial use in applying various fluids to the working surfaces of molds, dies or other similar forming apparatus.
The State of the Art is shown by the following patent and other publications and technical data sheets:
U.s. pat. No. 2,953,305 issued Sept. 20, 1960 to Bondurant; PA0 Paasche Airbrush Co., Catalog No. 7165 available from Paasche Airbrush Co., 1909 Diversey Parkway, Chicago, Ill. 60614; PA0 Acheson Product Data Sheet for Dag Handgun Models 090, 086, and 098 available from Dag Engineering B. V., P. O. Box 8, Scheemda, Holland; PA0 Rimrock Corp. data sheets for Handgun Models, 090, 080, 081, 082, 083, and 084 available from Rimrock Corp., 1700 Rimrock Road, Columbus, Ohio 43219; and, W. E. Lang product data sheets for type A, B, C, AW, BW, and CW spray guns available from W. E. Lang, 6523 Nottingham, St. Louis, Mo. 63109.
In many industrial forming processes, such as, the molding, die-casting, drawing, and forging of various metals or other similar materials, it is necessary to apply a lubricant to the working surfaces of such dies or other forming apparatus between machine-cycle operations. Also, it is often desirable to blow air across these working surfaces to remove scale, sediment or other impurities which may have remained adhered thereto from previous operational cycles. Further, the application of air and lubricant to these working surfaces tends to cool the dies between operational cycles thereby prolonging the life of the dies. In certain cases it may also be desirable to apply a suitable release agent to promote removal of the finished article upon completion of the operational cycle.
Various types of hand operated spray guns have been developed for these applications, all of which employ separate valve mechanisms to control each of the fluids to be applied. These separate valves may be either operated by a single lever arm coupled to each valve or by separate lever arms for actuation of either valve independently of the other. Such devices thus require separate valve chambers for each fluid being dispensed, a valve core member for each chamber and appropriate seals for each valve all of which serve to make such devices relatively expensive to manufacture. This duplication of parts also increases the weight of such spray guns thus making them more difficult and cumbersome for an operator to handle as well as contributing substantially to operator fatique. Further, as the number of seals and other moving parts is necessarily increased, maintenance and repair costs of such multiple valve devices may be comparatively high. Also, as such hand spray guns are subjected to extremely adverse environmental conditions during use due to the nature of this foundry-type work and the proximity to high temperatures, these additional moving parts increase the potential for failure of the device, which may require shutting down a machine until repairs or replacement can be accomplished.
Accordingly, it is an object of the present invention to provide a manually operated spray gun which minimizes the number of moving parts required while affording the operational flexibility provided by multiple valved spray guns.
It is also an object of the present invention to provide a manually operated spray gun which is economical to construct, extremely durable in operation, and minimizes repair and maintenance costs.
It is a further object of the present invention to provide a spray gun employing fewer moving parts and associated support structure which is therefore lighter in weight, easier to use, and substantially reduces operator fatigue.
It is a still further object of the present invention to provide a spray gun which allows selective application of single fluids or simultaneous application of two or more fluids.
It is yet another object of the present invention to provide a spray gun which is relatively simple in construction thereby minimizing the potential failure.